In the field of orthopedic surgery there are various procedures requiring insertion of an anchor, pin, peg, screw or cage into the bones of the skeleton to correct anatomical defects. Other procedures include reconstruction, such as artificial joints and teeth. All of these procedures, requiring fixations of an appliance in the bone are currently performed using threaded connections between the components.
For example, in hip replacements using modular joints, the artificial head of the hip joint is screwed on the end of a pin fixed in the femur. Torque applied to the head of the joint will normally be translated to the pin. In many spinal corrections, pedicle screws are placed in the vertebrae to support cages or plates for fixing spatial orientation. The connection of the screws to the ancillary devices usually put torque on the vertebrae through the pedicle screw. Similarly, in placing artificial teeth on pegs inserted in the jaw bone, torque may be applied through the fitting of the teeth.